Masa harina is a fine corn flour you can find in large grocery or specialty stores.
You also will need a large pot of boiling water for blanching the husks and a setup for steaming the tamales, such as a bamboo steamer and wok.
Shuck the corn carefully so as to preserve the husks. To do this, cut off the stem end of the ear close to the base. Carefully peel off the husks from the bottom of the ear, keeping them intact. Trim off any dried or discolored areas from the top of each husk. Blanch the corn ears in boiling water for 5 minutes. Remove and drain well. Blanch the husks in same water for 3 minutes. Remove and drain well. Discard the water. Remove kernels from the corn cobs. Discard cobs.
To make the masa filling, beat the lard in a large bowl until light and fluffy, the same way you would cream shortening when making a cake. This may take as long as 3 minutes. Use an electric mixer on medium speed. Begin adding the masa, about 1/2 cup at a time while beating constantly. Scrape down the sides of the bowl often. If the mixture becomes too stiff, beat in some of the warmed chicken broth, a little at a time. Beat in the salt. The masa is ready when it is very delicate and light and has the consistency of buttercream frosting. Any leftover masa can be frozen.
Place a large, blanched husk on work surface, vertically, with the pointed end of the husk facing away from you. Spread the center of the husk with a generous 1 tbs of masa mixture. Add about 2 tsp of blanched corn and about 2 tsp cooked chicken on top of the masa. If you run out of large husks, lay 2 smaller husks side-by-side. Adjust the amount of filling according to the size of the husk. Fold the tamales like this:.
First, fold the long sides of the husk inward over the filling. If these edges are curling, make sure they are flat when folding. Then, fold the top of the husk over the filling. Finally, fold up the bottom edge of the husk to make a square-ish packet, about 1 3/4 to 2 inches square. If the tamale is difficult to fold, trim off the thick, stem end of the husk. Some cooks tie the tamale closed with long, thin strips of husk or cotton kitchen twine.
Lay each completed tamale, face up, carefully into the steamer. You can use a two-level steamer with no problem. Steam over vigorously boiling water for about 1 hour, adding additional water to the steamer as needed. Remove from steamer to a serving plate. Cool briefly.
To eat, unfold the tamale, top with your favorite salsa or condiment, scoop out the filling and enjoy. Red and green salsa for serving, along with guacamole and sour cream are good choices. A good accompanying dish is Mexican red rice. Just search "mexican red rice" on Recipezaar. Discard the corn husk.